Potential impact of subsonic and supersonic aircraft exhaust on water vapor in the lower stratosphere assessed via a trajectory model

[1] We employ a trajectory model to assess the impact on the stratosphere of water vapor present in the exhaust of subsonic and a proposed fleet of supersonic aircraft. Air parcels into which water vapor from aircraft exhaust has been injected are run through a 6-year simulation in the trajectory model using meteorological data from the UKMO analyses with emissions dictated by the standard 2015 emissions scenario. For the subsonic aircraft, our results suggest maximum enhancements of ∼150 ppbv just above the Northern Hemisphere tropopause and of much less than 50 ppbv in most other regions. Inserting the perturbed water vapor profiles into a radiative transfer model, but not considering the impact of additional cirrus formation resulting from emissions by subsonic aircraft, we find that the impact of subsonic water vapor emissions on the radiative balance is negligible. For the supersonic case, our results show maximum enhancements of ∼1.5 ppmv in the tropical stratosphere near 20 km. Much of the remaining stratosphere between 12 and 25 km sees enhancements of greater than 0.1 ppmv, although enhancements above 35 km are generally less than 50 ppbv, in contrast to previous 2-D and 3-D model studies. Radiative calculations based upon these projected water vapor perturbations indicate they may cause a nonnegligible impact on tropical temperature profiles. Since our trajectory model includes no chemistry and our radiative calculations use the most extreme water vapor perturbations, our results should be viewed as upper limits on the potential impacts.

[1]  J. Hansen,et al.  Radiative cooling by stratospheric water vapor: Big differences in GCM results , 2001 .

[2]  Richard Swinbank,et al.  A Stratosphere-Troposphere Data Assimilation System , 1994 .

[3]  Andrew Gettelman,et al.  Direct deposition of subsonic aircraft emissions into the stratosphere , 1999 .

[4]  S. Wofsy,et al.  Removal of Stratospheric O3 by Radicals: In Situ Measurements of OH, HO2, NO, NO2, ClO, and BrO , 1994, Science.

[5]  S. Bakan,et al.  Contrail frequency over Europe from NOAA-satellite images , 1994 .

[6]  M. Schoeberl,et al.  A Lagrangian estimate of aircraft effluent lifetime , 1998 .

[7]  R. V. Dorland,et al.  Greenhouse effects of aircraft emissions as calculated by a radiative transfer model , 1995 .

[8]  Anne R. Douglass,et al.  A 5‐year simulation of supersonic aircraft emission transport using a three‐dimensional model , 1996 .

[9]  J. Penner,et al.  Aviation and the Global Atmosphere , 1999 .

[10]  S. Solomon,et al.  Buffering interactions in the modeled response of stratospheric O3 to increased NO x and HO x , 1999 .

[11]  M. Schoeberl,et al.  A Lagrangian simulation of supersonic and subsonic aircraft exhaust emissions , 2000 .

[12]  R. Sausen,et al.  Simulating the global atmospheric response to aircraft water vapour emissions and contrails: a first approach using a GCM , 1996 .

[13]  D. Kinnison,et al.  The Global Modeling Initiative assessment model: Application to high-speed civil transport perturbation , 2001 .

[14]  R. Sausen,et al.  Estimate of the Climate Impact of Cryoplanes , 2001 .

[15]  E. Browell,et al.  The impact of subvisible cirrus clouds near the tropical tropopause on stratospheric water vapor , 1998 .

[16]  A. Gettelman The evolution of aircraft emissions in the stratosphere , 1998 .

[17]  M. Chou,et al.  Broadband water vapor transmission functions for atmospheric IR flux computations , 1984 .

[18]  Robert Sausen,et al.  European scientific assessment of the atmospheric effects of aircraft emissions , 1998 .

[19]  G. Aeppli,et al.  Proceedings of the International School of Physics Enrico Fermi , 1994 .

[20]  S. Baughcum,et al.  Scheduled civil aircraft emission inventories for 1992: Database development and analysis , 1996 .

[21]  Modeled impact of cirrus cloud increases along aircraft flight paths , 2000 .

[22]  M. Chipperfield,et al.  The effects of future supersonic aircraft on stratospheric chemistry modeled with varying meteorology , 2000 .

[23]  P. Newman,et al.  Computations of diabatic descent in the stratospheric polar vortex , 1994 .

[24]  D. Rind,et al.  Climatic effect of water vapor release in the upper troposphere , 1996 .

[25]  R. Sausen,et al.  Aviation fuel tracer simulation: Model intercomparison and implications , 1998 .

[26]  J. Barnett,et al.  Monthly mean global climatology of temperature, wind, geopotential height, and pressure for 0 - 120 km , 1990 .